package cn.group.hotel2.filter;

import cn.group.hotel2.security.LoginPrincipal;
import cn.group.hotel2.web.JsonResult;
import cn.group.hotel2.web.ServiceCode;
import com.alibaba.fastjson.JSON;
import io.jsonwebtoken.*;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import org.springframework.web.filter.OncePerRequestFilter;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

/**
 * @author wcl
 * @version 0.0.1
 * @date 2022/11/8
 * @apiNote JWT过滤器
 */
@Slf4j
@Component
public class JwtAuthorizationFilter extends OncePerRequestFilter {

    @Value("${hotel2.jwt.secret-key}")
    private String secretKey;

    public static final int JWT_MIN_LENGTH = 113;

    public JwtAuthorizationFilter() {
        log.debug("创建过滤器对象:JwtAuthorizationFilter");
    }

    @Override
    protected void doFilterInternal(HttpServletRequest request,
                                    HttpServletResponse response,
                                    FilterChain filterChain) throws ServletException, IOException {
        log.debug("JwtAuthorizationFilter开始执行过滤...");

        SecurityContextHolder.clearContext();

        // 获取客户端携带的JWT
        String jwt = request.getHeader("Authorization");
        log.debug("获取客户端携带的JWT,{}", jwt);

        // 检查是否获取到了基本有效的JWT
        if (!StringUtils.hasText(jwt) || jwt.length() < JWT_MIN_LENGTH) {
            log.debug("获取到的JWT被视为无效,当前过滤器将放行...");
            filterChain.doFilter(request, response);
            return;
        }

        // 尝试解析JWT
        log.debug("获取到的JWT被视为有效,准备解析JWT...");
        response.setContentType("application/json; charset=utf-8");
        Claims claims = null;
        try {
            claims = Jwts.parser()
                    .setSigningKey(secretKey)
                    .parseClaimsJws(jwt)
                    .getBody();
        } catch (ExpiredJwtException e) {
            log.debug("解析JWT时出现ExpiredJwtException");
            String message = "非法访问！";
            JsonResult<Void> jsonResult = JsonResult.fail(ServiceCode.ERR_JWT_EXPIRED, message);
            String jsonResultString = JSON.toJSONString(jsonResult);
            PrintWriter writer = response.getWriter();
            writer.println(jsonResultString);
            return;
        } catch (MalformedJwtException e) {
            log.debug("解析JWT时出现MalformedJwtException");
            String message = "非法访问！";
            JsonResult<Void> jsonResult = JsonResult.fail(ServiceCode.ERR_JWT_MALFORMED, message);
            String jsonResultString = JSON.toJSONString(jsonResult);
            PrintWriter writer = response.getWriter();
            writer.println(jsonResultString);
            return;
        } catch (SignatureException e) {
            log.debug("解析JWT时出现SignatureException");
            String message = "登录信息已过期,请重新登录！";
            JsonResult<Void> jsonResult = JsonResult.fail(ServiceCode.ERR_JWT_SIGNATURE, message);
            String jsonResultString = JSON.toJSONString(jsonResult);
            PrintWriter writer = response.getWriter();
            writer.println(jsonResultString);
            return;
        } catch (Throwable e) {
            log.debug("解析JWT时出现Throwable,需要开发人员在JWT过滤器进行异常处理!");
            String message = "您有异常没有处理,请根据服务器控制台的信息来处理相关的异常!";
            PrintWriter writer = response.getWriter();
            writer.println(message);
            e.printStackTrace();
            return;
        }

        // 获取JWT中的管理员信息
        String username = claims.get("username", String.class);
        Long id = claims.get("id", Long.class);
        String authoritiesJsonString = claims.get("authorities", String.class);

        // 处理权限信息
        List<SimpleGrantedAuthority> authorities
                = JSON.parseArray(authoritiesJsonString, SimpleGrantedAuthority.class);

        // 创建Authentication对象
        LoginPrincipal loginPrincipal = new LoginPrincipal(id, username);
        Authentication authentication
                = new UsernamePasswordAuthenticationToken(
                    loginPrincipal, null, authorities);

        // 将Authentication对象存入到SecurityContext
        log.debug("准备向SecurityContent中存入认证信息,{}", authentication);
        SecurityContextHolder.getContext().setAuthentication(authentication);

        // 过滤器链继续向后传递，即：放行
        log.debug("JWT过滤器执行完毕,放行!");
        filterChain.doFilter(request, response);
    }
//    public static void main(String[] args){
//
//        Map<String, Object> user = new HashMap<>();
//        user.put("username", "wang");
//        user.put("password", "123456");
//        String jwt = createJWT(UUID.randomUUID().toString(), JSON.toJSONString(user), 3600 * 24);
//
//        System.out.println("加密后：" + jwt);
//
////        //解密
////        Claims claims = parseJWT(jwt);
////        System.out.println("解密后：" + claims.getSubject());
//    }
}
